Electronic evaporator dryer for eliminating odors in vehicle air conditioning systems

ABSTRACT

An apparatus and method for drying condensate from the heat exchanger of a vehicle&#39;s air conditioning system after operation in order to thwart odor buildup is provided. The apparatus and method operate regardless of whether the system&#39;s blower control circuit is positively or negatively switched. The apparatus includes relays that bypass the normal operating electrical routing to the air conditioning system&#39;s blower motor to operate the blower directly. The method comprises determining that the engine of the vehicle has been switched off and that the air conditioning system of the vehicle was in operation prior to the engine being switched off. If the conditions are met, the air conditioning system&#39;s blower is operated on a predetermined time schedule to circulate air in the air conditioning system to dry condensate therefrom. In this way, growth of odor-causing fungus and bacteria is inhibited.

This application claims priority to U.S. provisional patent application,U.S. Ser. No. 60/285,935, filed Apr. 23, 2001, and incorporates in itsentirety this provisional patent application as if fully set forthherein.

TECHNICAL FIELD

The invention disclosed herein relates generally to automotive airconditioning systems and more particularly to the prevention of moisturebuild-up within such air conditioning systems with the goal ofeliminating the promulgation of fungus and bacteria and the odor thatresults therefrom.

INCORPORATION OF PRE-EXISTING PATENT DISCLOSURE

This disclosure incorporates in its entirety the disclosure, claims, anddrawings of U.S. Pat. No. 5,899,082 issued May 4, 1999 and filed on Sep.18, 1997 as if fully set forth herein. This patent will be referred toherein as the “incorporated reference.”

BACKGROUND

As discussed in detail in the incorporated disclosure, automotive airconditioning systems are provided in most vehicles to cool the passengercompartment of the vehicle during hot weather. In general, automotiveair conditioning systems comprise a compressor coupled to the enginethat compresses a refrigerant to its liquid state. The compressed liquidrefrigerant is then delivered to a heat exchanger known as an evaporatorwithin the ductwork of the air conditioning system, where it is allowedto expand and thereby cools the evaporator. A blower forces air acrossthe evaporator and into the passenger compartment of the vehicle. As theair passes through the evaporator, it is cooled and the latent heat thatwas contained in the air is transferred to the refrigerant within theevaporator. Thus, the passenger compartment receives cool air. Theheated refrigerant is then passed through a radiator where it is cooledand delivered back to the compressor where the cycle begins anew.

As warm air from the passenger compartment is blown through theevaporator of an automobile air conditioning system to be cooled, watervapor contained in the air condenses on the surfaces of the evaporatorand on surrounding surfaces. During normal operation of the vehicle, thewater that condenses on the evaporator simply runs to the bottom of theevaporator and is drained from the air conditioning system onto theroadway. However, when the vehicle's engine is shut off and the airconditioning is no longer in operation, the condensed water on theevaporator begins to evaporate slowly within the ductwork of the airconditioning system and, as a result, a damp dank atmosphere is created.Such an atmosphere is ideal for the growth of mold, mildew, fungus, andbacteria within the ductwork of the system and particularly on the moistand wet surfaces of the evaporator. The growth of such organisms, inturn, results in a stale and unpleasant odor within the passengercompartment itself and can lead to air-borne spores and other organismsthat are unhealthy for the occupants of the vehicle.

In the past, there have been attempts to address the problems ofmicroorganism build-up within automotive air conditioning systems. Forexample, disinfectants and/or deodorizers may be sprayed into the airconditioning system to coat the surfaces thereof to prevent the growthof mold, mildew, and other fungus and bacteria within the ductwork.While this approach can prevent the build-up of odor causing organismsor mask their odors, at least in the short term, it still does notaddress the fundamental cause of such build-up, i.e., the moist, dampatmosphere within the air conditioning system.

The invention disclosed and claimed in the incorporated referenceapproaches the problem by preventing the establishment of a moistatmosphere within the air conditioning system that is conducive to thegrowth of unwanted microorganisms. In general, this invention comprisesa method of drying the interior and evaporator of a vehicle's airconditioning system to thwart the propagation of fungus and bacteria andits attendant odor. The method comprises the steps of determining thatthe engine of the vehicle has been switched off, determining that theair conditioning system was in operation prior to the engine beingswitched off, and, upon determining that both of these conditions exist,operating the blower of the vehicle's air conditioning system on apredetermined time schedule to draw air through the system for dryingcondensate from interior surfaces thereof. To carry out thismethodology, the incorporated reference discloses an electronic controlcircuit coupled to the blower motor of the vehicle air conditioningsystem. When the circuit senses that the engine has been shut off afterair conditioning operation, it activates a relay on a predetermined timeschedule, such as once every ten minutes, for a predetermined period oftime. The intermittent scheduled operation of the blower draws out andremoves evaporated condensate from within the air conditioning systemand, at the end of several cycles, all of the condensate has been driedand removed. Thus, the fundamental cause of the growth of undesirablemicroorganisms, i.e., the moist, damp atmosphere within the airconditioning system, is eliminated and such organisms do not tend togrow in the resulting dry atmosphere.

Operation of a vehicle's air conditioning blower motor on apredetermined time schedule after operation of the air conditioningsystem as disclosed in the incorporated reference has proven to be asuccessful solution to the problems of micro-organism growth and itsattendant odor in vehicles. However, the Electronic Evaporator Dryer(EED) circuitry taught in the incorporated reference for carrying outthe methodology, while very successful for use within some automotiveblower wiring schemes, nevertheless is not useable with certain otherwiring schemes found in the automotive industry. More particularly, therelay of the EED circuitry in the incorporated reference is spliced intothe blower motor circuit downstream of positively switched blowercontrol circuits of the system. The other terminal of the blower motoris connected directly to ground in these “positively switched” systems.During the drying operation, the relay of the EED circuit is activatedto disconnect the positive terminal of the blower motor from the blowercontrol circuitry and to connect it to directly to the positive terminalof the vehicle's battery. Thus, when the relay is activated, the blowermotor is operated at maximum speed to dry interior surfaces of the airconditioning system. Operation of the blower at its maximum speed ishighly desirable to achieve the best and quickest drying.

While the foregoing EED circuitry works well for systems wherein theblower motor is positively switched, i.e. switched and controlled on thepositive side of the motor, it does not operate well in systems wherethe blower control circuitry of the air conditioning system is“negatively switched” or, in other words, switched to ground. In such anegatively switched system, the positive terminal of the blower motornormally is connected directly to the accessory switch of the vehicleand the negative terminal of the blower motor is connected to groundthrough the blower control circuit. The blower control circuit includesa blower switch for turning the blower on and off and an array ofresistors for controlling the speed of the blower motor as it runsduring normal operation of the vehicle.

Thus, during the drying operation, if the positive terminal of theblower only is connected through the EED relay to the positive terminalof the battery, the blower motor in most cases will not operate atmaximum speed because the negative terminal of the blower is connectedto ground through the speed control resistor network of the blowercontrol. In some cases where a driver has turned the blower to the “off”position in a negatively switched scheme, the blower, using the EEDcircuit of the incorporated reference, will not operate at all duringthe evaporator drying cycle. Thus, there is a need for an improved EEDcontrol circuit for carrying out the methodology that is applicable toand works with blower motor wiring and control schemes wherein theblower motor is positively switched and controlled and also works withwiring schemes wherein the blower motor is negatively switched andcontrolled. It is to the provision of such a circuit and the methodologycarried out by the circuit that the present invention is primarilydirected.

SUMMARY

Briefly described, the present invention comprises an apparatus andmethod for eliminating odors arising from the growth of organisms withina vehicle's air conditioning system.

In one embodiment, the present invention encompasses an apparatus foruse with a vehicle's air conditioning system. The apparatus generallyincludes a first relay connected to a positive terminal of a blowermotor of the vehicle's air conditioning system, and a second relayconnected to a negative terminal of said blower motor. These relays arecoupled to a logic circuit that cooperates with them to bypass both theair conditioning system's blower control and the vehicle's accessoryswitch to connect the blower motor terminals to the positive terminal ofthe battery and also to ground.

Another embodiment includes a vehicle air conditioning system. The airconditioning system generally includes a compressor through whichrefrigerant flows to an evaporator. A blower cooperates with theevaporator to cool the refrigerant. The blower includes a blower controland a blower motor having a positive terminal and a negative terminal.The air conditioning system also includes a bypass circuit that bypassesboth the blower control and the accessory switch to connect the blowermotor terminals directly to the positive terminal of a battery and toground, to operate the blower during the drying cycles. For example, thebypass circuit may include a logic circuit connected to a temperaturesensor and/or a battery voltage sensor. When the appropriate conditionsare noted by these sensors, the logic circuit can activate the controlcircuit to connect the blower terminals to the battery and ground toactivate the blower at its maximum speed.

In another embodiment, an apparatus for use with a vehicle airconditioning system to dry condensate from the heat exchanger of thesystem to prevent propagation of fungus and bacteria and resulting odorsis provided. The apparatus includes a logic circuit connected to both abattery voltage sensor and a temperature sensor. The logic circuit alsois operatively coupled to a first relay that selectively switches thepositive terminal of the blower motor of the air conditioning system tothe positive terminal of the vehicle's battery. A second relay is alsoconnected to the logic circuit. This second relay is selectivelyswitches the negative terminal of the blower motor to ground.

Among the general aspects of the present invention is a method of dryingcondensate from the heat exchanger of a vehicle's air conditioningsystem to thwart the propagation of fungus and bacteria and itsattendant odor. The method includes the step of determining that theengine has been switched off, as well as sensing the ambient temperatureand determining that the air conditioning system of the vehicle was inoperation prior to the engine being switched off if the sensed ambienttemperature is greater than a predetermined threshold. The method alsoincludes operating the blower of the vehicle's air conditioning systemon a predetermined time schedule to draw air through the airconditioning system for drying condensate from interior surfacesthereof, wherein operating the blower includes bypassing the blowercontrol circuit.

These and other features, objects, and advantages of the invention willbecome more apparent upon review of the detailed description set forthbelow when taken in conjunction with the accompanying drawing figures,which are briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified illustration of a first type of wiring schemefound in vehicle air conditioning systems wherein the blower motor ispositively switched and controlled by a blower control circuit.

FIG. 2 is a simplified illustration of a second blower motor wiringscheme wherein the blower motor is negatively switched and controlled bya blower control.

FIG. 3 is a functional diagrammatic illustration of an EED circuitaccording to the present invention showing the connections to anegatively switched blower motor of a vehicle for carrying out theinvention.

FIG. 4 is another functional diagrammatic illustration of an EED circuitaccording to the present invention showing connection to a positivelyswitched blower motor of a vehicle for carrying out the invention.

FIG. 5 is a detailed electronic schematic diagram of an EED circuitry ofthe present invention with a positively switched arrangement.

FIG. 6 is a detailed electronic schematic diagram of an EED circuitry ofthe present invention with a negatively switched arrangement.

FIG. 7 is a diagrammatic representation of a vehicle air conditioningsystem encompassing aspects of the present invention.

DETAILED DESCRIPTION

Referring now in more detail to the drawings, in which like numeralsrefer to like parts throughout the several views, FIGS. 1 and 2 arepresented to illustrate two common types of wiring and blower controlschemes 11 and 111 used in vehicles for controlling the blower motor ofthe vehicle's air conditioning system. FIG. 1 illustrates a “positivelyswitched” blower motor control system 11 and FIG. 2 illustrates a“negatively switched” blower motor control system 111. Referring to FIG.1, a blower motor 12 of an automotive air conditioning system has apositive terminal 13 and a negative terminal 14. The negative terminal14 is connected directly to ground 16. The positive terminal 13 isconnected to the positive battery terminal 22 through a blower switchand resistor network 17 (or blower control circuit) and through theaccessory or key switch 21 inside the automobile. The blower controlcircuit 17 includes an array of resistors 18 and a manually operatedcontrol knob 19 within the vehicle. The control knob 19 can be rotatedor otherwise manipulated to connect the blower motor 12 through any oneof the resistors to the positive terminal 22 of the battery or to turnoff the blower motor. The resistances of resistors in the network 18 areselected such that the blower motor 12 can be operated at a variety ofspeeds depending upon the position of the control knob 19. It thus willbe seen that in this wiring scheme, the speed of the blower motor 12 iscontrolled by switching one of the resistors in the network 18 in serieswith the positive side of the circuit, thus the designation “positivelyswitched.”

Referring to FIG. 2, which illustrates a negatively switched blowercontrol scheme 111, the blower motor 12 again has positive terminal 13and a negative terminal 14. The positive terminal 13 is connected to thepositive battery terminal 31 through the accessory or key switch 29within the vehicle. The negative terminal 14 of the blower motor 12 isconnected to ground 34 through a blower switch and resistor network (orblower control circuit) 32 having a speed control resistor network 33,as discussed above. With such a negatively switched wiring scheme 111,the positive terminal 13 of the blower motor 12 is always connecteddirectly to the positive terminal 31 of the battery during operation ofthe vehicle. The blower motor speed is controlled (or the blower motoris shut completely off) by manipulating the control knob 36 to select aparticular resistor and place it in series with the negative terminal 14of the blower motor 12. Thus, the designation “negatively switched.”

FIGS. 3 and 4 illustrate in simplified black box form an EED circuitaccording to the invention coupled to blower motor control systems forcarrying out methods of the invention. In FIG. 3, the blower motorcontrol system is illustrated as being one alterative employing anegatively switched wiring scheme similar to that of FIG. 2, whereasFIG. 4 illustrates a positively switched wiring scheme similar to thatof FIG. 1. For this purpose, Box 46 is indicated as being the accessoryswitch, whereas Box 48 is the blower control circuit. In FIG. 3, theblower control 48 connects the negative terminal 14 of the blower motor12 to ground, whereas in FIG. 4 the blower control 48 connects thepositive terminal 13 of blower motor 12 to the positive terminal of thevehicle's battery through the accessory switch 46. The EED unit 51 ofthe present invention works equally well with either wiring scheme.

The EED unit includes a first relay 52 and a second relay 53. The coilsof each relay are connected to and activated by the logic circuits 63 ofthe unit, which are described in more detail below. The first relay 52is a single-pole double-throw type relay having a battery pole 56, anaccessory switch pole 58, and a common or switch pole 54. The switchpole 54 is connected to the accessory switch pole 58 when the relay isin its inactivated state and to the battery pole 56 when the relay isactivated. Accessory switch pole 58 is said to be “normally closed” andbattery pole 56 is “normally open.”

The first relay 52 is spliced in series with the wire 44 that connectsthe positive terminal of the battery to the positive terminal 13 of theblower motor 12 through the accessory switch 46 and, possibly, blowercontrol 48, depending upon whether blower control 48 is connected toaccessory switch 46 or to ground. Wire 44 is cut and connected to theswitch pole 54 and accessory switch pole 58. Since accessory switch pole58 is normally closed, wire 44 connects the positive terminal 13 ofblower motor 12 to the positive terminal of the battery through theaccessory switch 46, possibly blower control 48, and first relay 52under normal operating conditions.

A second relay 53, which also may be a single-pole double-throw relay,has an unconnected pole 62, which is normally closed, a ground pole 61,which is normally open and a second switch pole 59, which switchesbetween the first two poles. The switch pole 59 of the relay 53 iselectrically connected to the wire 47 that connects the negativeterminal 14 of the blower motor 12 to ground, possibly through theblower control 48, depending upon the wiring scheme. Under normaloperating conditions, the second relay 53 is in its inactive state,wherein second switch pole 59 is switched to unconnected switch pole 62.When the second relay 53 is activated, switch pole 59 switches to groundpole 61 so that the normal connection between the negative terminal 14to ground is bypassed. Thus, if blower control 48 is connected toground, as shown in FIG. 3, the blower control 48 is bypassed when thesecond relay 53 is activated.

The logic circuits 63 within the EED module 51 are configured andprogrammed to activate the first and second relays 52 and 53 underpredetermined conditions. More specifically, and as described in moredetail in the incorporated reference and below, the logic circuitsinclude a temperature sensor and a battery voltage sensor. The batteryvoltage sensor is monitored to determine when the engine of the vehiclehas been shut off and the temperature sensor is monitored to determinewhen the ambient temperature is above a predetermined threshold, suchas, for example, 60° F. When these sensors indicate that the engine hasbeen shut off and that the temperature is above the threshold, apresumption is made that the air conditioning system of the vehicle hasbeen in operation. At this point, the logic circuit activates both therelay 52 and the relay 53 simultaneously, then deactivates, and againactivates them repeatedly in a predetermined timing schedule. In otherwords, the relays are activated for a predetermined time, deactivatedfor a predetermined time, again activated for a predetermined time, andso on through a pre-established number of cycles.

Each time the relays 52 and 53 are activated as described above, thefollowing occurs. First, the positive terminal 13 of the blower motor isdisconnected from the accessory switch and possibly the blower control,depending upon the wiring scheme in use, as the switch pole 54 of therelay moves into contact with the battery pole 56. When the switch pole54 engages the battery pole 56, which is connected directly to thepositive terminal 57 of the battery, the positive terminal 13 of theblower motor 12 becomes directly connected to the positive terminal 57of the battery through the relay 52. At the same time, the switch pole59 of the second relay 53 moves to engage the ground pole 61 of therelay. When this occurs, the wire 47 normally connecting the negativeterminal 14 of the blower motor 12 to ground, and possibly the blowercontrol 48, depending upon the wiring scheme, is shunted directly toground through ground pole 61 of second relay 53.

Accordingly, it will be seen that when the relays 52 and 53 are eachactivated, the positive terminal 13 of the blower motor becomesconnected directly to the positive terminal of the battery and thenegative terminal of the blower motor becomes connected directly toground. As a result, the blower motor is operated at its full speed aslong as the relays 52 and 53 are each activated. This result ensuesregardless of whether the wiring scheme in use in the particular vehicleis a positively switched wiring scheme as in FIG. 1 or a negativelyswitched wiring scheme as in FIG. 2. This is because all of the blowercontrol circuitry, whether it is on the positive or negative side of theblower motor, is bypassed and the blower motor is connected, regardlessof the wiring scheme, directly to the positive terminal of the batteryand to ground. Thus, the EED circuit of the present invention, unlikethat of the incorporated reference, is equally applicable withoutmodification both to positively and negatively switched blower motorwiring schemes.

FIGS. 5 and 6 are electronic schematic diagrams of circuits for carryingout the present invention in a positively switched arrangement and anegatively switched arrangement respectively. Many of the electroniccomponents in these diagrams are the same as or functionally similar tothose illustrated in the incorporated reference and therefore discussionin great detail is not required here. Generally, however, FIG. 5illustrates a blower motor 12 having a positive terminal 13 and anegative terminal 14. The positive terminal 13 is connected to theblower control circuit, which, in turn is connected to the accessoryswitch and the positive terminal of the battery. The negative terminal14 of the blower motor is connected to ground. FIG. 6 illustrates theinvention within the context of a negatively switched arrangement,wherein the positive terminal 13 of the blower motor is connected to theaccessory switch and the negative terminal of the blower motor isconnected through the blower control circuit to ground. First and secondrelays 52 and 53 are illustrated in electronic schematic form in FIGS. 5and 6, but will be seen to function as described with respect to FIGS. 3and 4. More particularly, the first relay 52 is spliced in series withthe wire connecting the positive terminal of the blower motor and thesecond relay 53 is shunted to the wire connecting the negative terminalof the blower motor.

The electronic components of the logic circuit 53 are illustratedenclosed in a dashed or phantom-lined box 63. Conditioned power tooperate the electronic components of the logic circuit 63 is provided bya power supply and surge suppressor circuit 66, which is commonlyunderstood by those of skill in the art.

The logic circuits 63 include a micro-controller chip 67, which, in theillustrated embodiment, is a PIC12C508-04-/SM chip. Such amicro-controller chip can be programmed with software to monitor variousones of its inputs and to control its outputs according to the conditionof the inputs and the dictates of its programming. One of the inputs ofthe micro-controller 67 is connected to an ambient temperature sensor 68and another input is connected to a battery voltage sensor 69, asdescribed in some detail in the incorporated reference. One of theoutputs of the micro-controller 67 is connected to a transistor switchcircuit 71, which, in turn, is coupled to the coils of the first andsecond relays 52 and 53.

The micro-controller 67 is programmed essentially as described in theincorporated reference. In general, the ambient temperature sensor 68 ismonitored by the micro-controller 67 to determine the ambienttemperature. The voltage sensor 69 is monitored to determine the batteryvoltage, which typically falls below a predetermined threshold when theengine is shut off after operation. When a drop in the battery voltageindicates that the engine has been running but has been shut off and, atthe same time, the ambient temperature is high enough such that theprobability is good that the air conditioning system has been operating,the software in the micro-controller then sets its output to activatethe transistor switch circuit 71 and, in turn, the relays 52 and 53.When this occurs, the blower motor is attached directly to the batteryand ground as described above such that the blower motor operates atfull speed so long as the relays 52 and 53 are activated.

After a relatively short period of operation, such as, for example, 10seconds, the micro-controller 67 deactivates the relays 52 and 53, whichshuts off the blower motor. The blower motor is left off for apredetermined time, such as, for example, 30 minutes. During this time,condensed moisture on interior surfaces within the air conditioningsystem evaporates and the air within the ductwork of the system becomessaturated with moisture. At this point, the micro-controller 67 againactivates the relays to operate the blower motor for a relatively shortperiod of time in order to draw the moisture-saturated air out of theinterior of the air conditioning ductwork. This cycle is repeated over aperiod of, for example, two hours, at the end of which time all of theresidual condensate on surfaces within the air conditioning system isevaporated and removed from the air conditioning ductwork. Accordingly,at the end of the predetermined time schedule, the evaporator and otherinterior surfaces within the air conditioning system are dried such thatmildew, fungus, mold, and other microorganisms do not tend to growthere. As an ultimate result, odor within the vehicle is essentiallyeliminated for the life of the vehicle.

As shown in FIG. 7, an air-conditioning system 100 of the presentinvention is provided. A compressor 88, an evaporator 90, andrefrigerant 86 are shown in diagrammatic form to represent the generalelements of an air-conditioning system. The refrigerant 86 is flowablethrough both the compressor 88, which compresses the refrigerant 86, andthe evaporator 90, in which the refrigerant 86 absorbs heat. A blower 92is also provided that cooperates with the evaporator 90 to provide airflow through the evaporator and into the vehicle to cool the passengercompartment thereof. The blower 92 may be controlled through eitheralternative blower control scheme described above and shown in FIGS.3-6. The blower 92 may be activated when the engine is turned off, asdescribed above, to remove condensate from the evaporator 90 and,possibly, other portions of the air-conditioning system 100 where itmight develop. The result is a reduction in the propagation ofodor-causing fungus and bacteria, thereby reducing odors originating inthe air-conditioning system.

The invention has been described in terms of preferred embodiments andmethodologies. It will be obvious to those of skill in the art, however,that various additions, deletions, and modifications to the preferredembodiments may be made, are within the spirit and scope of theinvention.

What is claimed is:
 1. An apparatus for operating the blower of anautomotive air conditioning system on a predetermined timed schedulefollowing operation of the air conditioning system to remove condensatefrom the interior of the air conditioning system and thus to thwartattendant odors, the blower having a positive terminal and a negativeterminal, said apparatus comprising: a first relay coupled to thepositive terminal of the blower, said first relay, when activated,electrically connecting the positive terminal of the blower to thepositive terminal of the automotive battery; a second relay coupled tothe negative terminal of the blower, said second relay, when activated,electrically connecting the negative terminal of the blower to ground;and a logic circuit operatively coupled to said first and second relays,said logic circuit being configured to activate said first relay andsaid second relay on a predetermined time schedule when the automotiveair conditioning system is turned off after having been operated toremove moisture from within the air conditioning system and thereby toeliminate an atmosphere therein that is conducive to the growth ofmicro-organisms that cause undesirable odor.
 2. The apparatus of claim1, wherein said first relay includes a battery pole connected to thepositive terminal of the automotive said battery.
 3. The apparatus ofclaim 2, wherein said first relay includes an accessory switch poleconnected to the positive terminal of the automotive battery through anaccessory switch.
 4. The apparatus of claim 3, wherein said accessoryswitch pole is connected to said accessory switch through a blowercontrol circuit of the air-conditioning system.
 5. The apparatus ofclaim 1, wherein said second relay includes an unconnected pole.
 6. Theapparatus of claim 5, wherein said second relay includes a ground pole.7. The apparatus of claim 1, wherein said logic circuit is connected toa temperature sensor for determining ambient temperature.
 8. Theapparatus of claim 1, wherein said logic circuit is connected to abattery voltage sensor for monitoring battery voltage.
 9. The apparatusof claim 1, wherein said negative terminal of said blower motor isconnected to ground through a blower control circuit of theair-conditioning system.
 10. An air conditioning system for a vehiclecomprising: a compressor coupled to an engine of the vehicle; anevaporator in flow communication with said compressor; a refrigerantflowable through said compressor and said evaporator; a blowercooperating with said evaporator, said blower including a blower controland a blower motor having a positive terminal and a negative terminal;and, a circuit bypassing said blower control and an accessory switch ofthe vehicle and connecting said positive terminal of said blower motorto a positive terminal of a battery of the vehicle and connecting saidnegative terminal of said blower motor to ground on a predetermined timeschedule when the air conditioning system is turned off after havingbeen operated.
 11. The air-conditioning system of claim 10, wherein saidcircuit includes a logic circuit.
 12. The air-conditioning system ofclaim 11, wherein said logic circuit is connected to a temperaturesensor.
 13. The air-conditioning system of claim 11, wherein said logiccircuit is connected to a battery voltage sensor.
 14. Theair-conditioning system of claim 10, wherein said circuit includes afirst relay and a second relay.
 15. The air-conditioning system of claim14, wherein said first relay includes a battery pole connected to saidpositive terminal of said battery.
 16. The air conditioning system ofclaim 14, wherein said first relay includes an accessory switch poleconnected to said positive terminal of said battery by an accessoryswitch.
 17. The air-conditioning system of claim 16, wherein saidaccessory switch pole is connected to said accessory switch through saidblower control.
 18. The air-conditioning system of claim 14, whereinsaid second relay includes an unconnected pole.
 19. The air-conditioningsystem of claim 14, wherein said second relay includes a ground pole.20. The air-conditioning system of claim 14, wherein said negativeterminal of said blower motor is connected to ground through said blowercontrol.
 21. The air-conditioning system of claim 14, wherein said firstrelay and said second relay are connected to a logic circuit.
 22. Theair-conditioning system of claim 21, wherein said logic circuit isconnected to a temperature sensor.
 23. The air-conditioning system ofclaim 21, wherein said logic circuit is connected to a battery voltagesensor.
 24. An apparatus for use with an air conditioning system of avehicle to dry condensate from the heat exchanger of the airconditioning system in order to prevent propagation of fungus andbacteria and resulting odors, said apparatus comprising: a logic circuitconnected to a battery voltage sensor and a temperature sensor; a firstrelay connected to said logic circuit, to a positive terminal of ablower motor of the air conditioning system and through two connectionsto a positive terminal of a battery of the vehicle; and, a second relayconnected to said logic circuit, to a negative terminal of said blowermotor, and through two connections to ground.
 25. The apparatus of claim24, wherein said two connections connecting said first relay to saidpositive terminal of said battery include a direct connection and anindirect connection through an accessory switch.
 26. The apparatus ofclaim 25, wherein said indirect connection is also through a blowercontrol.
 27. The apparatus of claim 24, wherein said two connectionsconnecting said second relay to ground include a direction connection toground and an indirect connection to ground through a blower control.28. A method of drying condensate from the heat exchanger of a vehicle'sair conditioning system to thwart the propagation of fungus and bacteriaand its attendant odor, said method comprising the steps of: determiningthat the engine has been switched off; sensing the ambient temperatureand determining that the air conditioning system of the vehicle was inoperation prior to the engine being switched off if the sensed ambienttemperature is greater than a predetermined threshold; operating theblower of the vehicle's air conditioning system on a predetermined timeschedule to draw air through the air conditioning system for dryingcondensate from interior surfaces thereof, wherein operating the blowerincludes bypassing the blower control of the blower.
 29. The method ofclaim 28, wherein operating the blower includes connecting the positiveterminal of the blower motor directly to the positive terminal of thevehicle's battery and connecting the negative terminal of the blowermotor directly to ground.
 30. A method of drying condensate from withinan vehicle's air conditioning system to thwart the propagation of fungusand bacteria and its attendant odor, the air conditioning system havinga blower with a positive terminal and a negative terminal, said methodcomprising the steps of: (a) determining that the engine of the vehiclehas been shut off after having been operated; (b) connecting thepositive terminal of the blower directly to a positive voltage sourcefrom the vehicles battery and connecting the negative terminal of theblower directly to ground to operate the blower; (c) after apredetermined time, disconnecting at least one of the terminals of theblower that was connected in step (b) to discontinue operation of theblower; (d) repeating steps (b) and (c) for a predetermined number ofcycles, the cycled operation of the blower drawing condensate fromwithin the air conditioning system to thwart the propagation of fungusand bacteria therein.
 31. The method of claim 30 and wherein step (c)comprises disconnecting the positive terminal of the blower from thesource of positive voltage and disconnecting the negative terminal ofthe blower from ground.
 32. The method of claim 30 and wherein step (a)comprises monitoring the voltage level of the vehicle's battery anddetermining that the engine has been shut off when the monitored voltagefalls below a predetermined threshold after having been above thethreshold.
 33. The method of claim 30 and further comprising the step,in conjunction with step (a), of determining that the vehicle's airconditioning system was in operation prior to the engine being shut offbefore proceeding to step (b).
 34. The method of claim 33 and whereinthe step of determining that the vehicle's air condition system was inoperation comprises sensing an ambient temperature and concluding thatthe air conditioning system was in operation if the sensed ambienttemperature is above a predetermined threshold.
 35. The method of claim30 and wherein step (b) further includes disconnecting the positiveterminal of the blower from its normal connection while it is connecteddirectly to the positive voltage source and disconnecting the negativeterminal of the blower from it normal connection while it is connecteddirectly to ground.
 36. The method of claim 35 and wherein the positiveterminal's normal connection includes connection through a blowercontrol circuit of the air conditioning system to a source of positivevoltage from the vehicles battery.
 37. The method of claim 35 andwherein the negative terminal's normal connection includes connectionthrough a blower control circuit of the air conditioning system toground.